Railway switch point detector



April 3, 1934. L B E 1,953,461

RAILWAY SWITCH POINTDETECTOR FiledMaroh 30, 1932 3 Sheets-Sheet 1 Hi5"ATTORNEY.

April 1934- H 1.. BONE 1,953,461

RAILWAY SWITCH POINT DETECTOR Filed March C50, 1932 3 Sheets-Sheet 2INVENTOR.

Herbert L. Bone HIS A TT ORNE Y.

April 3, 1934. H. BONE 1,953,461

RAILWAY SWITCH POINT DETECTOR Filed March 30, 1932 3 Sheets-Sheet 5INVENTOR. Ho bo z L.B0120.

HIS A T TOR N E Y.

Patented Apr. 3, 1934 warren srarss PATENT OFFICE RAILWAY SWITCH POINTDETECTOR Application March 30, 1932, Serial No. 602,024

29 Claims.

My invention relates to railway switch point detectors;

One object of my invention is to insure the safety of trains andvehicles moving over railway switches. 1

It is customary in automatic block signal territory and at interlockingsto provide at each switch a circuit controller which is operated in partby the mechanism of the switch machine, and lb? in part by a detectorrod or rods attached to the switch points, and the function of whichisto so control the signals governing traiiic over the switch that theywill indicate stop unless the switch points occupy their properpositions rela- 131. tive to the stock rails and are locked in' thesepositions. When, by error, a switch is trailed through, the switchpoints are displaced at the top an amount which would easily operate thecircuit controller if the connection of the point 2'0? detector rod orrods with the points could be made at the top of the points. However,for clearance reasons, it is necessary to connect the detector rods tothe switch points some distance below the top of the points, where, dueto the rolling of the points during the trailing, the amount of themovement may not be more than one-half of that occurring at the top;and, furthermore, aftera train has trailed throughthe switch, the pointswill usually spring back toward their orig- 301 inal positions a certainamount. As a result, the

final displacement of the point detector rod or rods may be very little,if any, more than the displacement which would correspond to a maximumpermissible opening of the closed switch point, (which is the setting atwhich the circuit controller would be adjusted to operate the indicationcontacts), while the opening of the closed point at the top might besufiicient'to be extremely dangerous for subsequent high speed trainmove ments. In order to insure that this dangerous condition will bedetected, I provide an improved latching mechanism for holding theindication contacts in their operated positions after they are onceoperated until they are released by a maintainer. Thus, even though theswitch points spring back toward their proper positions after the trainhas trailed through the switch, the signals governing trailic over theswitch will continue to display a restrictive indication until themaintainer releases the latching mechanism and permits the contacts ofthe circuit controller to return to their normal positions; It isassumed that before the maintainer does this, he will inspect the switchpoints and, if damaged, repair them, thus guarding against adangerouscondition due to damaged switch points.

I will describe one form of point detectors embodying my invention, andwill then point out the novel features thereof in claims.

In the accompanying drawings, Fig. l is atop plan view showing a railwayswitch operated by a switch machine E provided with a point detectorembodying my invention. Fig. 2 is a top plan view of the point detectorand some of the associated parts of the switch machine E, certain partsbeing broken away or removed for clearness. Fig. 3 is a verticalsectional view taken substantially on the line III-III of Fig. 2, butdrawn to a somewhat smaller scale than Fig. 2. Fig. i is a view of aportion of the latch mechanism forming part of the point detector shownin Figs. 2 and 3, and embodyingmy invention. Fig. 5 is an elevationalview of the portion of the latch mechanism shown in Fig. 4. Fig. 6 is asectional view taken on the line VIVI of Fig. 5. Fig. 7 is a fragmentarysectional view taken on the line VII VII of Fig. 2. Fig. 8 is afragmentary sectional view taken on the line VIII- VIII of Fig. 3. Fig.9 is a detail view showing the so cam 16 forming part of my pointdetector, and one of the contacts'controlled thereby, as they appearwhen viewed from the left in Fig. 8.

Similar reference characters refer to similar parts in each of theseveral views;

Referring first to Fig. 1, the referencechar-' aoter M designates arailway switch comprising, as usual, two fixed rails B and B and twomovable switch points A and A The fixed rails B and B are laid on tieplates 1 and arese- 9o" cured to the crossties 2 in the usual manner.The switch points'Aand A are connected together for simultaneousmovement by a bridle rod 3 and a front rod 4', and the bridle rod 3, inturn, is connected to the operating rod 0 of a switch machine E, wherebythe switch may be moved into a normal or areverse position. When theswitch occupies its normal position, in which it is illustrated in Fig.1, the switch point A engages the fixed rail B, and the switch point A166 is spaced a slight distance from the fixed rail B When the switch isreversed, however, the

switch point A then engages the fixed rail B and the switch point A isspaced from the rail B.

Extending into one end of switch machine E is a lock rod L and a pointdetector rod P. The" lock-rod L is slidably mounted in suitable guidesin the switch machine for horizontal, movements in directions parallelto the operating'rod O and, W W

as here shown,'has its right-hand end 5 formed 0 integral with the frontrod 4. The point detec tor rod P is also slidably mounted in suitableguides in the switch machine E for movements in directions parallel tothe operating rod 0 and lock rod L, and has one end connected to theswitch point A by means of a connecting rod 6 and a bracket '7. It willbe noted that, as here shown, the lock rod L and the point detector rodeach comprise two bars, suitable means being provided to permit relativelongitudinal movements between the bars of each rod for the purpose ofadjustment.

While a point detector embodying my invention may be applied to a switchmachine of any suitable type, the switch machine E to which I have shownit applied in the drawings is similar in all respects to the switchmachine shown and described in an application for Letters Patent of theUnited States, Serial No. 600,601, filed by William C. McWhirter, onMarch 23, 1932, for Railway switch operating apparatus. Inasmuch as theconstruction and operation of the switch machine E is similar to thatdescribed in the said McWhirter application, only those parts which arethought to be essential for a clear understanding of my presentinvention have been shown in detail in the drawings, and will bedescribed here.

Referring now particularly to Figs. 2, 3 and 8, the point detectorembodying my invention is here shown as comprising a suitable circuitcontroller which is located within the casing of the switch machinedirectly above the lock rod L and point detector rod P, and which isoperated in part by a slide bar N. The slide bar N extendslongitudinally of the switch machine and is provided on its upper facewith two locking dogs 8 and 9. When the switch points occupy theirnormal positions in which they are shown in Fig.

'1, the slide bar N occupies the extreme position in which it is shownin Figs. 2 and 3, and under these conditions, the locking dog 8 enters apair of notches 100 in the lock rod L to lock the switch points in theirnormal positions. When, however, the switch machine is operated to movethe switch points to their reverse positions, the slide bar N is movedby the operating mechanism, prior to the movement or" the operating rod0 which reverses the switch, toward the left, as viewed in Figs. 2 and3, to an intermediate position in which the dogS is withdrawn from thenotches 100 in the lock rod L, thus unlocking the switch; and when themovement of the switch to its full reverse position by the operating rodhas been completed, the slide bar N is then moved in the same directionas before, to another extreme position in which the locking dog 9.enters another pair of notches (not shown) in the lock rod L, thuslocking the switch in its reverse position. When the switch machine isnext operated to restore the switch to its normal position, thesubsequent movements of the slide bar and operating rod above describedare maintained, but the directions of the movements are reversed.

Formed in the upper face of the locking dog 9 are rack teeth 10 whichmesh with an idler gear 12. The idler gear 12, in turn, meshes with agear 13. which is secured to a cam shaft 14. As shown in Fig. 2, the camshaft 14 is journalled at its ends in suitable bearings formed in asupporting casting 15, and has fixed thereto two spaced cams 16 and 16which are concentric therewith. The cam 16 is provided in its peripherywith a notch 17 (see Figs. 3 and 8), and is adapted when rotated, toactuate a pair of contact fingers 18 which are connected together forsimultaneous movement by an insulating bridge 19 The cam 16 is likewiseprovided in its periphery with a notch 17 as shown in Fig. 9, and isadapted when rotated to actuate a pair of contact fingers 18 which areconnected together for simultaneous movement by an insulating bridge 19The two pairs of contact fingers 18 and 18 are provided with rollers 20and 20*, respectively, which cooperate with the corresponding cams 16and 16 and serve as an actuating medium for the contact fingers when theassociated cams are rotated. When the rollers 20 or 20 is in alignmentwith the notch 17 or 17 in the associated cam, the fingers 18 or 18 moveto an inclined position in which the associated roller enters thealigned notch, except under certain conditions which will be describedhereinafter, and when in this inclined position, these fingers engagelower fixed contact fingers 21 21 or 21 21 When, how ever, the rollersare riding on the peripheries of the associated cams, the contactfingers 18 or 18 are lifted to cause the inner finger or" each pair toengage an upper stationary contact member 22. As here shown, the partsare so arranged and so proportioned that the notch 17 in the cam 16 willalign with the roller 20 when and only when the slide bar N occupies theextreme position in which it looks the switch in its normal position asshown in the drawings, and that the notch 1'? in the cam 16 will alignwith the roller 20 when and only when the slide bar N occupies theextreme position in which it looks the switch in its reverse position.

The contact fingers 18 and 18 are further controlled in accordance withthe positions of the switch points'by suitable means which I will nowdescribe. As here shown, these means comprise two crossbars 23 and 23slidably mounted in the framework 15 directly below the cam shaft 14,and extending at right angles to the point detector rod P in parallelspaced relation. The crossbar 23 is provided with a roller 24 and isbiased by means of a spring 25 in such direction that the roller 24constantly engages the lefthand edges, as viewed in Fig. 2, of thedetector bars of the point detector rod P. The crossbar 23 is likewiseprovided with a roller 24 and is biased by means of a spring 25 in suchdirection that the roller 24 constantly engages the righthand edges, asviewed in Fig. 2, of the detector bars of the point detector rod P.Formed in the left and right-hand edges, respectively, of the detectorbars of the point detector P, and cooperating with the rollers 24 and 24are normal and reverse notches 26 and 26. These notches are soproportioned and the bars of the detector rod are so adjusted that thenormal notches 2G will receive the roller 2 1 when and only when theswitch occupies its normal position and the switch point A is closed inthe proper manner, and that the reverse notches 26* will receive theroller 24* when and only when the switch occupies its reverse positionand the switch point A is properly closed.

The crossbar 23 operates a cam member 27, and the crossbar 23 operates acam member 2'7 (see Figs. 3 and 8). The cam member 2''! is journalled onthe cam shaft 14 adjacent the cam 16 and is provided with a downwardlyextending gear segment 28* which meshes with rack teeth 29 formed on theupper side of the crossbar 23 in such manner that this cam member willbe rotated whenever crossbar 23 moves. The cam member 27 is alsoprovided with an upwardly extending cam segment 30 which cooperates withthe roller 20 carried by the contact fingers 18 The cam member 27 issimilarly journalled on the cam shaft 14: adjacent the cam 16 and isprovided with a downwardly extending gear segment 28 which meshes withrack teeth 29 formed on the upper side of the crossbar 23 and with anupwardly extending cam segment i which cooperates with the roller 20carried by the contact fingers 18 The upper portions of the camsegments, as here shown, are curved and are provided with notches 31 and31 respectively. The parts are so proportioned that the notch 31 willalign with the roller 20 when and only when the roller 24 on thecrossbar 23 is within the normal notches 26 in the detector rod P, andthat the notch 31* will align with the roller 20' when and only when theroller 24* on the crossbar 23 is within the reverse notches in thedetector rod P. It will be seen, therefore, from the foregoing that whenthe switch occupies its normal position in which it is shown in Fig. l,and is locked in this position by the slide bar N, the notch 31 in thecam segment 30 and the notch 1'7 in the cam w will both align withroller 20 carried by the contact fingers 18 and under these conditions,the contact fingers 18 will assume their inclined positions in which thecontacts 18 21 are closed. and the contact l8* 22 is open. Likewise,when the switch occupies its reverse position, and is locked in thisposition by the slide bar N, the notch 31 the cam segment 30* and thenotch if? in the cam 16* will both align with the roller 20* carried bythe contact fingers 18 and under these conditions, the contact fingers18 will assume their inclined positions in which the contacts 18 -21 areclosed, and the contact Ri -22 is open. When, however, the switch isbeing moved from one extreme position to the other extreme position, thenotch 31 in the cam segment 30 and the notch l7 in the cam 16* will bothbe out of alignment with the roller and the notch 31 in the cam segmentand the notch 17 in the cam l6 will both be out of alignment with theroller 20 and under these conditions, both sets of contact fingers 18and 18 will be held in their raised positions, so that the contacts Mi-22 and 18 22 will be closed while the contacts l8 -2l and Ri -21 willall be open.

It will be noted that the crossbars 23 and 23 are each provided with asecond roller 32 or 32 These rollers are adapted to cooperate with asecond point detector rod, not shown, which would be provided ininstallations where the switch machine A is utilized to operate a doubleslip switch or a movable point frog. In either instance, both pairs ofswitch points would have to occupy their proper positions relative tothe fixed rails, and the closed points would have to be properlyadjusted before either pair of contact fingers would move to theirinclined positions. A second rod might also be utilized in connectionwith a single slip switch in the event that it is desired to control thecircuit controller by both switch points instead of by only one switchpoint, as shown in the drawings. Under these conditions both switchpoints would have to occupy their proper positions relative to the stockrails before either pair of fingers would move to their inclinedpositions, as will be readily understood.

As best seen in Fig. 2, a latching finger 34: is pivotally attachedintermediate its ends to one end of the crossbar 23 by means of a pin35,

and is provided at one end with a latch surface 36 and at the other endwith an axially extending slot 37*. The slot 3'7 receives a bolt 38 (seeFig. 7) which is secured to a lug 39 formed on the framework 15, and itwill be apparent, therefore, that any movement of the crossbar 23 willrotate the latching finger 3% about the bolt 38 as a fulcrum. It willalso be apparent, that since, as here shown, the crossbar 23 isconnected with the latching finger 34? near the middle of the finger,the distance through which the latch surface 36 is moved for a givenmovement of the crossbar will be nearly twice the distance through whichthe crossbar is moved. The latch surface 36 is adapted to cooperate witha vertically movable latch button e0 in a manner which will be describedhereinafter, and the bolt 38 is made eccentric so that, for any givenposition of the crossbar, the horizontal position of the latch surfacerelative to the left-hand side of the latch button, as viewed in Fig. 2,may be adjusted by turning this bolt. In order to facilitate the turningof the bolt, the upper. end of the bolt is provided with a saw kerf d2into which a screw driver or other suitable tool may be inserted.Vertical displacement of the latching finger at the end which isprovided with the latch surface is prevented by an overlying lug 41formed on the supporting casting 15. The parts'are so proportioned thatwhen the crossbar 23 occupies the position in which the roller 2 henters the normal notches 26 in the point detector rod P, as shown inFig. 2, the latching finger 34* will occupy the position in which thelatch surface 36 is superposed over the latch button 40, but that, whenthe crossbar 23 occupies the position in which the roller 24. is forcedout of the normal notches 26 in the point detector rod P, the latchingfinger 3% will be moved toward the left, as viewed in Fig. 2, to theposition in which the latch button 40, if raised, would just clear thelatch surface 36*. A latching finger 34*, similar to the latching finger34 is pivotally attached intermediate its ends to one end of thecrossbar 23 in the same manner as the latching finger 34 is attached tothe crossbar 23 and is provided at one end with a latch surface 36 whichcooperates with the latch button in such manner that the latch surface36* will be superposed over the latch button if) when the roller 24 1';

on the crossbar 23 is within the reverse notches 26 in the pointdetector rod P, but that, when the roller 241 in the crossbar 23 isforced out of the reverse notches 26 in the point detector rod P, thelatch surface 26 will then occupy the position in which it isillustrated in the drawings, so that the latch button 40, if raised,would clear this surface.

The latch button 40 forms part of a latching device, designated as awhole by the reference character C, and shown in detail in Figs. 4, 5,and 6. Referring now to Figs. 4, 5, and 6, the latching device Ccomprises a substantially horizontal latch arm 44: which is pivotallymounted at one end on a horizontal pin 45 carried by the spaced verticalsides 46 of a suitable supporting bracket 46. The arm 44 extends betweenvertical guides 47 formed on the upper edges of the sides 46 of thebracket 46, and is provided at its free end with a threaded hole 48 intowhich the latch button 10 is adjustably screwed. The latch button 40 ismaintained in an adjusted position by means of a suitable jam nut 49.Operatively connected with the latch arm 44 at the portion which islocated between the guides 47 is a spring roller on the bracket 46.

tappet 56 comprising a plunger 50 a spring 50 and a roller 56 (see Fig.6). The plunger 50 extends freely through a hole 51 in the arm 44, andis provided at its upper end with a nut 43, and at its lower end with abifurcated head 50 between the bifurcations of which the roller 50 ispivoted on a pin 50 They spring 50 surrounds the plunger 50 between thehead 50 and the underside of the arm 44, and is provided with suf-'ficientcompression so that, if the roller 50 is raised vertically, acorresponding vertical motion of the latch arm will take place providedthe resistance to the raising of the arm is not more than that whichwould reasonably be expected due to friction in the bearings and theweight of the arm. It follows, therefore, that if the resistance to theraising of the arm is greater than that resulting from friction in thebearings and the weight of the arm, due for example, to the latch buttonengaging the underside of one or the other of the latching fingers 34 or34* as will sometimes be the case under certain conditions which will bedescribed hereinafter, the spring 50 will become compressed, and thelatch arm will not be raised. The roller 50 is guided by a transverseslot 53 formed in the lower end of the bracket 45, which slot alsoserves to limit the amount of upward movement of the roller. Thelowermost position to which the arm 44 can drop is limited by twoshoulders 52 formed on the sides 46 of the bracket 46 adjacent theguides 47, as best seen in Figs. 5 and 6.

The latching device further comprises suitable means for automaticallymaintaining the latch arm in its uppermost position after it has oncebeen moved to this position, until it is manually restored to itslowermost or normal position. As. here shown, this means comprises alatch catch 54 pivoted on a pin 55 carried by a lug 56 formed The latchcatch 54 is provided with a vertical arm 54 and with a horizontal 54*.When the latch arm 44 occupies its lowermost position in which it isshown in Figs. 5 and 6, the arm 54 of the latch catch54 extends into anotch 57 formed in the side of the latch arm 44. When, however, thelatch arm 44 is moved to its uppermost position, the arm 54 of the latchcatch 54 becomes disengaged from the notch 57, and due to the bias of ahandle 54 formed on the arm 54' the latch catch 54 then moves to aposition in which a heel 54 on the arm engages a stop 54 formed on thebracket. 46. When in this latter position, the upper end of the verticalarm 54 engages the underside of the latch arm 44 and prevents the latcharm 44 from returning to its lowermost position. 'Tnus it will be seenthat once the latch arm 44 is raised, it will not be possible for it toreturn to its lowermost position until the latch catch is manuallyreturned to the position in which the vertical arm 54* aligns with thenotch 57 in the'latch arm 44.

The bracket 46 is attached to thesupporting casting 15 in such aposition that the roller 50 of the spring roller tappet 50 will enter arecess 58 (see Figs. 2 and 3) formed in the upper side of the siide barN when and only when the slide bar N occupies its intermediate position.'The parts are so proportioned that when the roller 50 is within therecess 58 in the slide bar N, the latch arm 44 will be permitted to moveto its lowermost position under the influence of gravity, but that, whenthe roller is out of the recess 58, as is the case when the slide baroccupies either of its two extreme positions, the arm 44 will then tendto move to its uppermcstposition under the action of the spring rollertappet 50. The parts are further so proportioned that if either of thelatching fingers 34 occupy the position in which the associated latchsurface 36 is superposed over the button 40 when the arm 44 is urgedupwardly by the spring roller tappet 50, the latch button 40 will engagethe underside of the superposed arm and prevent the arm from rising.

The operation of the apparatus as a whole is as follows: As shown in thedrawings, the switch occupies its normal position and is locked in thisposition by the slide bar N. The cam member 2'7 therefore occupies theposition in which the notch 31 in the cam segment 30 is in alignmentwith the roller 20 on the contact finger 18 and the cam 16 occupies theposition in which the notch 17 is also in alignment with the roller 20*;while the cam member 27 occupies the position in which the notch 31 inthe cam segment 30 is out of alignment with the roller 20* in thecontact fingers 18 and the cam 16 occupies the position in which thenotch 17 is out of alignment with the roller 20'. The contact fingers18, therefore, occupy their inclined positions in which the contacts Hi-21 are closed and the contact 1s -22 is open, and the contact fingers18 oocupy their raised positions in which the contacts 18 21 are openand the contact 18 22 is closed. Since the slide bar N occupies itsnormal extreme position, roller 55 of the spring roller tappet 50 is outof the recess 58 in the slide bar, and the spring roller tappet 50accordingly tends to raise the latch arm 44. The latch arm 44 isprevented from moving to its uppermost position under these conditions,however, because the latching finger 34 occupies the position in whichthe latch surface 36 is superposed above the latch button 45, as clearlyshown in Fig. 2.

T will now assume that with the parts inthe position just described, theswitch machine E is operated in a manner to move the switch from itsnormal to its reverse position. As previously pointed out, when theswitch machine is operated to reverse the switch, the slide bar N ismoved from the extreme position shown to an intermediate position priorto the movement of the operating rod which reverses the switch points,and to another extreme position upon the completion of the movement ofthe switch points to their reverse positions. During the movement of theslide bar N to its intermediate position, the cam 16 is rotated throughthe medium of the gears 12 and 13 to a position in which the notch 1'7is out of alignment with the roller 2-5) on the contact fingers 18 andthese contact fingers are, therefore, moved to their raised positions inwhich contacts HE -21 are open and contact le -22 is closed.Furthermore, during the movement of the slide bar N to its intermediateposition, the roller 56 of the spring roller tappet 50 of the latchingdevice C moves into the recess 58 in the slide bar N, thus releasing thecompression in the spring 50*, and hence permitting the latch arm 44 toremain in its lowermost position under the influence of gravity. As soonas the switch points start to move, the point detector rod P is ofcourse moved, and this movement forces the roller 24 on the crossbar 23out or" the normal notches 26 in the point detector rod. As a result,cam member 2'7 is rotated to the position in which the notch 31 in thecam segment 30 is out oi alignment with the roller 20 carried by thecontact fingers 18?, so that if cam 16% had failed to move these fingersto their raised positions during the movement ofv the slide bar N to itsintermediate position for any reason, they would now be moved to theirraised positions by the cam member 27 The movement of the crossbar 23due to the roller 24 being forced out of the normal notches 26 alsomoves the latching finger 34 in a counter-clockwise direction as viewedin Fig. 2 from the position in which the latch surface 36 overlies thelatch button 40 to the position in which the latch surface is located atone side of the latch button in the vertical plane. At this point in theoperation of the movement, both latching fingers 34 and 34 are clear ofthe latch button but, as described above, the roller 50 of the springroller tappet 50 is now within the notch 58 in the slide bar N, so thatthe latch arm remains in its lowermost position. When the switch pointshave reached their full reverse positions, point detector rod P occupiesthe position in which the reverse notches 26* are in alignment with theroller 20 on the crossbar 23 and the roller 24 therefore, moves into thereverse notches 26*, thus moving the latching finger 34 to the positionin which the latching surface 36 is above the latch button 40, and alsorotating the cam member 27' to the position in which the notch 31 in thecam segment 36' is in alignment with the roller 20 on the contactfingers 18 The fingers 18 are held in their raised positions by the cam16*, however, until the slide bar N completes its movement toward theleft,

as viewed in Figs. 2 and 3, to lock. the switch points in their reversepositions, at which time the cam 16* is rotated to the position in whichthe notch 17* is also in alignment with the roller 18*. When the notches31 and 18 are both in alignment with the roller 20, the contact fingers18 move to their inclined positions, thus closing contacts Ri --21 andopening contact 18 -22. The final movement of the slide bar N toward theleft also causes roller 50 of the spring roller tappet 50 of thelatching device C to move out of the recess 58 in the slide bar N, thusurging this latch arm to rise. This latch arm is now prevented fromrising, however, by the latch button 40 engaging the a underside of thelatching finger 34 If, when the switch occupies its reverse position,the switch machine E is operated to restore the switch to its normalposition, the subsequent movements of the parts just described ismaintained, but the direction of the movements is reversed. It isthought that the operation of the apparatus, under these conditions,will be readily understood from the foregoing and from an 1nspection ofthe drawings without describing it in detail.

I will next assume that with the parts in the positions in which theyare shown in the drawings, a train trails through the switch. Underthese conditions, each time a wheel passes through the switch, theclosed point A will be forced away from the associated fixed .rail B,thus moving the point detector rod P toward the right as viewed in Fig.l and upwardly as viewed in Fig. 2. This movement of the point detectorrod will normally force the roller 24* on the crossbar 23 out of thenormal notches 26 in the point detector rod so that the crossbar 23 willbe moved toward the left as viewed in Figs. 2 and 3. This movement ofthe crossbar 23 in turn, will rotate the cam member 27 to a position inwhich the roller 29 on the fin ers 18 is forced out of the notch 31 inthe cam segment thereby causing contacts 18 21 to become open, andcontact hi -22 to be come closed. The movement of the crossbar 23"" willalso rotate latching finger 34 to a position in which the latch surface36 is clear of the latch button 40, the parts being so adjusted that thelatch surface will reach the position in which it first clears the latchbutton 40 at the point in the movement of the crossbar where thecontacts 18' --2l first open or shortly thereafter, as desired. As soonas the latch surface 36* clears the latch button, the spring of thespring roller tappet 50 will force the latch arm as upwardly to itsuppermost position and, under these conditions, the head of the latchbutton will lie in the same vertical plane as the latch arm 34 After thelatch arm has been moved to its uppermost position, it will subsequentlybe held in this position by the latch catch 54 in the manner previouslydescribed. As a result, if, after the train has trailed completelythrough the" switch, the switch points tend to spring back toward theirnormal positions so as to restore the point detector rod to the positionin which the normal notches 26 again align with the roller 24*, latchsurface 36 will engage the edge of the head of the latch button 40 andprevent the crossbar from moving to the position in which the roller 24enters the normal notches. It follows, therefore, that under theseconditions, the indication contacts 18 -21 will remain open and thecontact 18 -22 will remain closed until the latch arm 44 is subsequentlyrestored to its lowermost position. In order to do this, it is necessaryfor an authorized person to manually restore the latch catch 54 to theposition in which it is shown in Fig. 5, and at the same time pushdownwardly on the latch arm 44. When the latch arm has been fullydepressed, the latch button 40 will be moved out of engagement with thelatch surface 36* of the latching finger 34 and if the points are thensafe for traffic to move over the switch, the spring 25 will 1 15restore the crossbar 23 to the position in which the roller 24 entersthe normal notches 26 in the point detector rod P, thus returning thelatching finger 34 to the position in which the latch surface 36overlies the latch 1'2'0 button 40. The movement of the crossbar 23" tothe position in which the roller 24 enters the normal notches 26 willalso rotate the cam member 27 to the position in which the notch 31 inthe cam segment 30 aligns with the roller 20 on the fingers 18 thuspermitting these fingers to move to their inclined positions in whichcontacts Ili -21 are closed, and the contact 81 -22 is open. It isassumed that the authorized person who manually operates the latch catchwill inspect the switch points, and, if damaged, repair them beforerestoring the latch arm to its lowermost position.

If, after the switch has been trailed in its normal position in themanner just described, the switch is moved to its reverse position bythe switch machine while the latch arm 44 is still in its uppermostposition, the contact fingers 18 will be held in their raised positionsdue to the movement of the point detector rod P caused by 140 thereversal of the switch points, and the contact fingers 18 will also beheld in their raised positions, because, even though the reverse notches:26 in the point detector rod then align with the roller 24 on thecrossbar 23 the latch but- 145 ton 40 will engage the latching surface36 of the latching'finger 34 and prevent the spring 25 from moving thecrossbar 23 to the position in which the roller 24* enters the reversenotches.

In the foregoing, it has been assumed that 150 while the switch wasbeing trailed in its normal position, the points would be moved farenough to force the roller 24 on the crossbar Z3 completely out of thenormal notches 26 in the point detector rod P. However, under certainconditions, the motion of the switch points will not be sufficient to dothis, and when this is the case, an additional action occurs involving asloping surface 40 formed on the upper portion of the edge of the latchbutton 40. To illustrate this action, I will assume that the points aredisplaced from their normal positions by the trailing movement an amountwhich moves the point detector rod P just far enough to cause thecontact fingers 18 to be raised to the positions to which they are outof engagement with the contact fingers 21 but which is not sufiicient toforce the'roller 2? completely out of the normal notches 26 Under theseconditions, the movement of the crossbar 23 which takes place will movelatching finger 34 far enough so that the latch surface 365 is justclear of the upper edge of the sloping surface 40 of the latch button40, and as soon as this happens, the spring 50 will start to force thelatch arm 44 upwardly. When the latch arm is forced upwardly, thesloping surface of the latch button acts as a wedge and causes furthermovement of the latching finger and crossbar; this further movement ofthe crossbar, in turn, causing the contact fingers 18 to move upwardlya. sufiicient amount to provide some margin for wear and inaccuracies inadjustment.

The operation of the apparatus after a train trails through the switchwhen the switch occupies its reverse position is similar to that whichtakes place when a train trails through the switch in its normalposition, and will be readily understood from an inspection of thedrawings without describing it in detail.

It should be pointed out that, while for purposes of description, I haveassumed that any abnormal displacement of the switch points from theirextreme positionswill be caused by a train trailing the switch, thepoints might also be displaced in some other manner, such for example,as by dragging equipment, and when this is the case, the apparatus willoperate in the same manner as it does when the displacement is due tothe switch being trailed.

Although I have herein shown and described only one form of pointdetectors embodying my invention, it is understood that various changesand modifications may be made therein within the scope of the appendedclaims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In a point detector for switch mechanisms having a slide bar forlocking the switch points in their extreme positions, a manuallyoperable latch catch, a latching member controlled by said slide bar andsaid latch catch, a point detector rod adapted to be connected with theswitch points to move therewith, a second member controlled jointly bysaid latching member and said point detector rod, and a contactcontrolled by said second member.

2. In a point detector for switch mechanisms having a slide bar forlocking the switch points in their extreme positions, a point detectorrod adapted to be connected with the switch points to move therewith, acrossbar controlled jointly by said slide bar and said detector rod, anda contact controlled jointly by said slide bar and said crossbar.

3. In combination with a railway switch and a slide bar for locking theswitch points in one extreme position, a point detector rod connectedwith the switch points to move therewith, a crossbar operated by saiddetector rod in such manner that said crossbar will normally move to afirst position when the switch points occupy said one extreme positionand to a second position when the switch points are moved away from saidone extreme position, and means controlled by said slide bar forpreventing said crossbar from returning to said first position if theswitch points are moved to said one extreme position after the switchhas been trailed by a train while the switch points are in the otherextreme position.

4. In combination with a railway switch and a slide bar for locking theswitch points in one extreme position, a point detector rod connectedwith the switch points to move therewith, a crossbar operated by saiddetector rod in such manner that said crossbar will normally move to afirst position when the switch points occupy said one extreme positionand to a second position when the switch points are moved away from saidone extreme position, and means controlled by said slide bar forpreventing said crossbar from moving to said first position after theswitch has been trailed by a train.

5. In combination with a railway switch and a slide bar for locking theswitch points in one extreme position, a point detector rod connectedwith the switch points to move therewith, a crossbar operated by saiddetector rod in such manner that said crossbar will normally move to afirst position when the switch points occupy said one extreme positionand to a second position when the switch points are moved away from saidone extreme position, a manually operable member and means controlled bysaid slide bar and by said manually operable member for preventing saidcrossbar from moving to said first position after the switch points havebeen moved away from said one position by a train trailing the switch.

6. In combination with a railway switch and a slide bar for locking theswitch points in one extreme position, a point detector rod connectedwith the switch points to move therewith, a crossbar operated by saiddetector rod in such manner that said crossbar will normally move to afirst position when the switch points occupy said one extreme positionand to a second position when the switch points are moved away from saidone extreme position, means controlled by said slide bar for preventingsaid crossbar from moving to said f rst position after the switch hasbeen trailed by a train until a manually operable member is operated,and a contact controlled by said crossban 7. In combination with arailway switch and a slide bar for locking the switch points in theirextreme positions, a point detector rod connected with the switch pointsto move therewith and provided with a notch, a crossbar provided with aroller which aligns with said notch when and only when the switch pointsoccupy one extreme position, means for biasing said bar in suchdirection that said roller will normally enter said notch when saidroller is in alignment with said notch, means controlled by said slideoar for preventing said crossbar from moving to the position in whichsaid roller enters said notch after a train trails through the switch,and a contact controlled by said crossbar.

8. In combination with a railway switch and a slide bar for locking theswitch points in their extreme positions, a point detector rodconnected. with the switch points to move therewith, a contact, meanscontrolled by said point detector rod .for operating said contact whenthe switch points are moved away from one extreme position, and meanscontrolled by said slide bar for retaining .said contact in its operatedposition until manua1- 1y released if and only if the movement of saidextreme positions, a member provided with a roller, a point detector rodconnected with the switch points to move therewith and provided .with .anotch which is adapted to receive said roller when and only when theswitch points occupy one extreme position, means for biasing said memberin such direction that said roller will normally enter said notch whenthe roller and notchare in alignment, means controlled by :said slide.bar for latching said member in the position in which said roller isout of said notch if the roller is forced out of the notch due to atrain trailing the switch when the switch points occupy said one extremeposition, and a contact controlled by said member.

10. In combination, a railway switch, a slide bar for locking the switchpoints in their extreme positions and provided with a recess, a'-contact, means for operating said contact when the switch points aremoved away from one extreme position, and means cooperating with saidrecess for'latching said contact in its operated position if and only ifthe switch pointsare forced away from said one extreme position whenlocked in such position by said slide bar.

'11. In combination, a railway switch, a slide 'bar for locking theswitch points in their extreme positions and provided with a recess, acontact, a point detector rod connected with the switch points to movetherewith, means controlled by said point detector rod for operatingsaid contact when th switch points are moved away from one extremeposition, and means cooperating with said recess for latching saidcontact in its operated position until manually released if and only ifthe switch points are forced away from said one extreme position whenlocked in such position by said slide bar.

12. In combination, a railway switch, a slide bar for locking the switchpoints in their extreme positions and provided with a recess, a pointdetector rod connected with the switch points to move therewith, amember, means for moving said member from one extreme position toanother extreme position when the switch points are moved away from oneextreme position, a contact which is operated when said member is movedto its other extreme position, and latching means controlled by saidrecess and effective for maintaining said member in its other extremeposition until manually released if and only if said member is moved toits other extrerne position while the switch points are locked in theone extreme position.

13. In combination, a railway switch, a slide bar for locking the switchpoints in their extreme positions and provided with a recess, a pointdetector rod connected with the switch points to move therewith, amember, means for moving said member from one extreme position toanother extreme position when the switch points are moved away from oneof their extreme positions, a contact which is operated when said memberis moved to .its other extreme position, a roller adapted to enter saidrecess in said slide bar when and only when said switch points areunlocked, and means controlled by said roller for latching said memberin its other extremeposition untilmanually released if said member ismoved to its other extreme position whil'esaid roller is out of saidrecess.

14. In a point detector for switch operating mechanisms having a slidebar for locking the switch points 'in their extreme positions, a firstcrossbar provided with a roller and biased to one position, a secondcrossbar provided with a roller and biased to one position, a detectorbar adapted to be connected with the switch points and provided with anormal notch which receives the roller on said first crossbar when andonly when said detector bar occupies a position corresponding vto thenormal position of the switch points and with a reverse notch whichreceives the roller on said second crossbar when and only when saiddetector bar occupies a position corresponding to the reverse positionof the switch points, means controlled by said slide bar for maintainingeither crossbar in the position in which the roller carried thereby isout of the cooperating notch in the detector bar if the roller on suchcrossbar is forced out of the associated notch when the slide bar is ina locking position, and two contacts one controlled by each crossbar.

15. In combination, a railway switch, a slide bar for locking the switchpoints in their extreme positions and provided with a recess, a latcharm, a latch button secured to said latch arm, a roller adapted to entersaid recess when and only when the slide bar occupies a position inwhich the switch points are unlocked, yieldable means controlled by saidroller and effective when and only when said roller is out of saidrecess for at times moving said latch arm from a first position to a 1second position, a latch catch for maintaining said latch arm in itssecond position after it has been moved to its second position, a pointdetector rod connected with the switch points to move therewith, amember biased to one position, means controlled by said detector rod formoving said member to another position in opposition to its bias whenthe switch points are moved away from one of their extreme positions, alatching finger pivotally mounted at one end and pivotally attachedintermediate its ends to said member and cooperating at its free endwith said latch button in such manner that said finger will overlie saidlatch button and prevent said latch arm from moving to its secondposition when said member occupies the position to which it is biasedbut not when said member is moved to its other position and that whensaid latch arm is moved to its second position said latching finger willengage said latch button and prevent said member from returning to theposition to which it is biased.

16. In combination, a railway switch, means for locking the switch inits extreme positions, a. latch button controlled by said locking meansand biased to a first position or a second position acposition, meanseffective when a train trails the switch for moving said latching fingerto a second position in which said latch button is free to move to itsfirst position, the parts being so proportioned that when said latchbutton occupies its first position it will prevent said latching fingerfrom returning to its first position under the action of its bias, and acontact controlled in accordance with the position of said latchingfinger.

17. In combination with a railway switch and a slide bar for locking theswitch points in one extreme position, a point detector rod connectedwith the switch points to move therewith, a crossbar operated by saiddetector rod in such manner that said crossbar will normally move to afirst position when th switch points occupy said one extreme positionand to a second position when the switch points are moved away from saidone extreme position, and means controlled by said slide bar forpreventing said crossbar from returning to said first position after itis moved away from said first position if and only if the movement ofsaid crossbar is due to the switch points being moved away from said oneextreme position while they are locked in said one extreme position.

13. In combination with a railway switch and a slide bar for locking theswitch points in one exwith the switch points to move therewith, acrossbar operated by said detector rod in such manner that said crossbarwill normally move to a first position when the switch points occupysaid one extreme position and to a second position when the switchpoints are moved away from said one extreme position, means controlledby said slide bar for preventing said crossbar from returning to saidfirst position after it is moved away from said first position if andonly if the movement of said crossbar is due to the switch po'nts beingmoved away from said one extreme position while they are locked in saidone extreme position, and a contact controlled by said cross- 45 bar.

19. In combination with a railway switch and a slide bar for locking theswitch points in one extreme position, a point detector rod connectedwith the switch points to move therewith, a crossbar operated by saiddetector rod in such manner that said crossbar will normally move to afirst position when the switch points occupy said one extreme positionand to a second position when the switch points are moved away from saidone extreme position, means controlled by said slide bar for preventingsaid crossbar from returning to said first position after it is movedaway from said first position if and only if the movement of saidcrossbar is due to the switch points being moved away from said oneextreme position while they are locked said one extreme position, and

a contact controlled jointly by said crossbar and said slide bar.

20. In combination with a railway switch and a slide bar for lock ng theswitch points in their extreme positions, a point detector rod connectedwith the switch points to move therewith, a contact, means controlled bysaid point detector rod for operating said contact when the switchpoints are moved away from one extreme position, and means controlled bysaid slide bar for retaining said contact in its operated position untilmanually released if and only if the movement of said points away fromsaid one position takes place treme position, a point detector rodconnected when the points are locked in said one extreme position.

21. In combination, a railway switch, a slide bar for locking the switchpoints in their two extreme positions, a detector rod connected with theswitch points, two contacts, means controlled by said detector rod foroperating the one contact when the switch points are moved away fromtheir one extreme position and for operating the other contact when theswitch points are moved away from their other extreme position, amanually operable member, and means controlled by said slide bar forlatching both contacts in their operated positions until said manuallyoperable member is subsequently operated if the switch points becomedisplaced while they are locked in either of their extreme positions.

22. In combination, a railway switch, a slide bar for locking the switchpoints in their extreme positions, a detector rod connected with theswitch points to move therewith and provided with two notches, a firstcrossbar provided with a roller and biased to such position that saidroller will enter the one notch in said detector rod when and only whenthe switch points occupy one extreme position, a second crossbarprovided with a roller and biased to such position that said roller willenter the other notch in said detector rod when and only when the switchpoints occupy the other extreme position, two contacts one controlled byeach crossbar and each arranged to be operated when the roller on theassociated crossbar is moved out of the cooperating notch insaiddetector rod, and means controlled by said slide bar for preventing bothcrossbars from moving to the position in which the roller carriedthereby enters the cooperating notch in said point detector rod if theroller on either crossbar is forced out of the cooperating notch in thedetector rod while the switch points are locked.

23. In combination, a railway switch, a slide bar for locking the switchpoints in their extreme positions, a detector rod connected with theswitch points to move therewith and provided with two notches, a firstcrossbar provided with a roller and biased to such position that saidroller will enter the one notch in said detector rod when and only whenthe switch points occupy one extreme position, a second crossbarprovided with a roller and biased to such position that said roller willenter the other notch in said point detector rod when and only when theswitch points occupy the other extreme position, two contacts onecontrolled by each crossbar and each arranged to be operated when theroller on the associated crossbar is moved out of the cooperating notchin said detector rod, a manually controlled member, and means controlledby said slide bar for preventing both crossbars from moving to theposition in which the roller carried thereby enters the cooperatingnotch in said detector rod until after said manually controlled memberis operated in the event that the roller on either crossbar is forcedout of the cooperating notch in said detector rod while the switchpoints are locked.

24. In combination, a railway switch, a slide bar for locking the switchpoints in their two extreme positions, a detector rod connected with theswitch points to move therewith and provided with two notches, a firstcrossbar provided with a roller and biased to such position that saidroller will enter the one notch in said detector rod when and only whenthe switch points occupy one extreme position, a second crossbarprovided with a roller and biased to such position that said roller willenter the other notch in said point detector rod when and only when theswitch points occupy the other extreme position, two contacts onecontrolled by each crossbar and each arranged to be operated when theroller on the associated crossbar is forced'out of the cooperating notchin said detector rod, a latch button provided on its upper edge with asloping surface and normally biased to one position, means including aspring and effective when and only when said switch points are locked bysaid slide bar for biasing said latch button toward another extremeposition, a first latching finger fulcrumed at one end for rotationabout a fixed pivot in the plane which said latch button occupics whenit is moved to its other extreme position and pivotally attachedintermediate its ends to said first crossbar and provided at its otherend with a latch surface which cooperates with said latch button, asecond latching finger fulcrumed at one end for rotation about a fixedpivot in the plane in which said latch button oc cupies when it is movedto its other extreme position and pivotally attached intermediate itsends to said second crossbar and provided at its other end with a latchsurface which cooperates with said latch button, the parts being soproportioned that when the roller on either crossbar is within thecooperating notch in said point detector rod the free end of theassociated latching finger will overlie said latch button and prevent itfrom moving to its second position but that when the roller on eithercrossbar is forced partway out of the cooperating notch in said pointdetector rod the associated latching finger will move to the position inwhich the latch surface of the finger is just clear of the inner edge ofthe sloping surface of said latch button, whereby if the switch pointsare then looked the spring associated with said latch button will forcesaid latch button to its other extreme position thus moving saidlatching finger, due to the sloping surface of said latch button, to theposition in which the roller on the associated crossbar is completelyout of the cooperating notch in said detector rod.

25. In combination, a railway switch, a slide bar for locking the switchpoints in their extreme positions, a detector rod connected with theswitch points to move therewith and provided with a notch, a memberprovided with a roller and biased to such position that said roller willenter said notch when and only when the switch points occupy one extremeposition, a contact controlled by said member and arranged to beoperated when said roller is moved out of said notch, and meanscontrolled by said slide 26. In combination, a railway switch, a slidebar for locking the switch points in their extreme positions, a detectorrod connected with the switch points to move therewith and provided witha notch, a member provided with a roller and biased to such positionthat said roller will enter said notch when and only when the switchpoints occupy one extreme position, a contact controlled by said memberand arranged to be operated when said roller is moved out of said notch,and means controlled by said slide bar and ef fective if said roller isforced partway out of said notch when the switch points are locked insaid one extreme position for moving said member to the position inwhich the roller is all of the Way out of said notch, and forsubsequently maintaining said member in this latter position until saidmember is manually released.

27. In combination with a railway switch and a member for locking theswitch in one of its extreme positions, a contact, means for operatingsaid contact when said switch is moved away from said one extremeposition, and means efiective if said switch is moved away from said oneextreme position when it is locked in such extreme position by saidmember for retaining said contact in its operated position until saidcontact is manually released.

28. In combination with a railway switch and a member for locking theswitch in one of its extreme positions, a contact, means for operatingsaid contact when said switch is moved away from said one extremeposition, and latching mechanism effective if said switch is moved awayfrom said one extreme position when it is locked in such extremeposition by said member for retaining said contact in its operatedposition until said contact is manually released.

29. In combination with a railway switch and a member for locking theswitch points in one extreme position, a point detector rod connectedwith one of said switch points, a contact, means controlled by saiddetector rod for operating said contact when the switch points are movedaway from said one extreme position, and means controlled by said memberfor retaining said contact in its operated position until said contactis manually released if and only if the movement of said points awayfrom said one extreme position takes place when the points are locked insaid one extreme position.

HERBERT L. BONE.

